The Arctic Sea freezes over. The Arctic Sea melts. This happens every year. The average date for the maximum extent of Arctic Sea ice, based on a period of 1981-2010, is March 12. The minimum extent is reached, on average, about September 15h.

Every year for the last several years, the minimum ice has been much lower than average in extent, and many years in a row have seen record minima. This is considered to be the result of global surface warming caused by human release of greenhouse gas pollution.

It is said that we can’t use the maximum ice cover to predict the minimum ice cover very accurately, because a lot of things can happen to affect the total ice cover during those many months of melting. However, the maximum ice amount for, say, 1979-1988 (the first ten years for which we have really good data on this) was high compared to the last ten year period, and correspondingly, the minimum extent was greater for that first ten year period than the most recent ten years, so there is a correlation. Still, the date of the maximum extent has tended to not move around much, and the same is true for the date of the minimum extent.

Bt maybe not this year. This year’s maximum Arctic Sea ice extent seems to have flatlined at a record low value, as shown in the graph above, from here. The current sea ice extent is that red line all by itself down near the bottom.

It may well be the case that the sea ice will start to re-freeze, and this line will go up again over the next two weeks or so, and max out near the historical average. The next week or so should be below freezing across much of the Arctic Sea, but there is a warm intrusion near Greenland and Europe, with above freezing air, expected to persist for that entire time. Overall, warm air and ice-breaking-up storms have invaded the Arctic repeatedly this winter. The sea ice extent may recover over the next several days, but I get the impression that most experts are quietly thinking it won’t.

This is not terribly surprising, given that the Earth’s surface temperatures are increasing, and sea ice is decreasing. This year, a El Ninño is adding fuel to the fire, as it were, and making these conditions even more extreme.

A concerning possible outcome is this: The Arctic Sea ice helps cool the planet by reflecting away sunlight. It is a reasonable assumption that during summers with much less ice, there is much less cooling. This can have impacts on the longer-lived fast ice* that is also melting in the arctic, and on nearby glaciers in greenland, and the planet overall. This is what is known as a “positive feedback” which is a somewhat misleading term, because this is not an especially “positive” event.

*CORRECTION: My friend and colleague Tenney Naumer, who watches both the weather and the Arctic very closely, contacted me to let me know that the “fast ice” is long gone. She told me, “In 2012, the ice in the channel between Ellesmere and Axel Heiberg Island (to the south of Ellesmere) melted out — that is the place where the ice had existed for more than 10,000 years. The Ward Hunt Ice Shelf broke off in 2002. The Ayles Ice Shelf broke off in 2005. In 2007, I watched (here) the ice break away from most of the Arctic side of the archipelago, and it has been all downhill since. It’s all gone now.”

The Arctic has, of course, been warming in step with anthropogenic global warming, plus more. This phenomenon has probably increased disruption to global weather systems, especially in the Northern Hemisphere, over the last decade or so.

But something somewhat novel is happening this year, presumably as a result of global warming combined with a strong El Nino. Storms are bringing extra warm conditions to the Arctic. A few days ago, the North Pole was above freezing, and over the next few days we are expecting more warm conditions in the Arctic Circle. See this post by Eric Holthaus.

Figuring that interesting things might be happening in the Arctic, I had a look at the National Snow and Ice Data Center interactive graphic showing Arctic Sea ice cover now and over time. The graphic is at the top of the post. It turns out that Arctic Sea ice is at an historic low for this date, and in fact, looks to be flatlining, at least for now. I presume the ice will expand again shortly when the current influx of warm air to the region subsides, but it will be interesting to see if we end up with a new minimal maximum of sea ice.

The surface ice in the Arctic has been melting to historic low levels every year for the last several years. The graph above shows the first ten years in the National Snow & Ice Data Center records, meant to indicate what Arctic Sea Ice “normally” does as it melts off during the northern warm months. The thick black line is the average over 1981-2010, and grey shaded area shows two standard deviations above and below that line. The blue line tracking along the lower end of the 2SD shaded area is the ice extent this year. During the period when sea ice is at its maximum, this year’s ice was low. This does not reliably predict the ultimate September minimum, but it is interesting that the sea ice extent is following an extreme course.

I’m reluctant to say anything about what will happen this year. The melting rate could slow, storms that may play a role in diminishing sea surface ice in the Arctic may not play a big role. Or, the rate of melt could increase and all the various factors that determine a year’s minimum could drive the ice off the sea to the extent that we have a record low. It would be very hard to beat the 2012 minimum extent, as that was an extreme year. But, that extreme year, show on the figure below, was not as low at the present time as the current extent.

The volume of sea ice is in some ways more important than the area it covers, because this reflects the overall Earth’s surface heat imbalance resulting from the human-induced greenhouse effect. Volume includes both new ice (formed over the previous winter) and old ice that does not melt at all in a given year. This old ice probably serves the role of keeping some of the new ice stable so it melts less, so there is a feedback. The more the volume reduces, the more the surface area may reduce, depending on various conditions.

Andy Lee Robinson has created, and regularly updated, an amazing graphic showing the change over time in Arctic sea ice volume.

Difference from average annual snow extent since 1971, compared to the 1966-2010 average (dashed line). Snow extents have largely been below-average since the late1980s. Graph adapted from Figure 1.1 (h) in the 2012 BAMS State of the Climate report.

90% of the Earth’s energy balance involves the ocean’s heat, shown here. Note that there is no current pause, and that surface temperature estimates (see graph above) tend to underestimate the total amount of anthropogenic global warming because much of this heat, routinely, goes into the ocean. We can expect some of this heat to return to the atmosphere in coming years.

Figure SPM.5. Solid lines are multi-model global averages of surface warming (relative to 1980–1999) for the scenarios A2, A1B and B1, shown as continuations of the 20th century simulations. Shading denotes the ±1 standard deviation range of individual model annual averages. The orange line is for the experiment where concentrations were held constant at year 2000 values. The grey bars at right indicate the best estimate (solid line within each bar) and the likely range assessed for the six SRES marker scenarios. The assessment of the best estimate and likely ranges in the grey bars includes the AOGCMs in the left part of the figure, as well as results from a hierarchy of independent models and observational constraints. {Figures 10.4 and 10.29}

… and figure that warming over coming decades will be at, near, or even above, the range previously estimated.

Arctic Sea Ice extent continues to be a problem. This year, according to the National Snow and Ice Data Center, ARctic Sea ice reached its lowest extent this year on September 17th, which is about the sixth lowest extent on record, following a multi-year trend of decline. There is variation from year to year. This year’s minimum was almost exactly the same as last years. With the exception of 2001, minimum extent has been below the climatalogical average every year since 1998.

The Arctic Sea is covered with ice during the winter, and some of it melts off every summer. Over recent years the amount of melt has been increasing. This is the time of year we may want to look at Arctic Sea ice because by late September it has reached its annual minimum and is starting to reform.

Looking at JUST surface area, which is one indicator of how warm the Arctic has become with Global Warming, we can see (above) that this years march of melting has been extreme, hugging the two standard deviation limit for all of the data from 1979 to 2010 (almost the present).

Here you can see that 2014 is distinctly different, with much more surface area loss, than the first ten years of this data set, from here.
And here you can see that 2014 is pretty much in the middle of the range for the “new normal” as represented by the most recent ten years:

So, in answer to the question above, 2014 was a very melty year in the Arctic, though over very recent years there have been worse years. This year is about the sixth lowest minimum extent since 1979 or before.

The graph above shows the 1981-2010 average plus or minus two standard deviations. Before going into more detail than that, you should look at the following graphic.

The top chart shows the march of Arctic Sea ice melt for first ten years of the baseline data set only, and the bottom chart shows the last ten years of the same data set. This tells us that the two Standard Deviations for the period 1981-2010 hides an important fact. Since Arctic Sea ice is melting more and more every year, a proper baseline might be the first several years of this period, not the entire period.

Now refer to the graphic at the top of the post. This is the current year’s ice extent. Notice that it is tracking right along the lower edge of the 2 Standard Deviation zone. In other words, the present year is exhibiting what we have been seeing all along: An Arctic with much less ice.

Now look at the years that post date the baseline period, 2011 through the present, including the wildy extreme year of 2012 when a record melt was set.

Here we see that collectively, the last three full years and the present partially documented year exist at the lower end of, or lower than, the 2 Standard Deviation zone. This suggests that the current trend is an extension of the previous couple of decades. More melting on average over time. One would hope this would level off, and maybe it will. But we certainly can not make that claim at this point.

Note that it is very hard to predict the ultimate minimum for a given year, even at this point. (Even so, I did it here way at the beginning of the season). We’ll have to wait and see.

Earth’s northern ice cap is heating up and melting down at an alarming, not previously predicted, rate. A paper just out in Wiley Interndisciplary Reviews: Climate Change, by Josefino Comiso and Dorothy Hall looks at recent historic transformations in the Arctic using satellite imagery, mainly from 1979 to the present. The decline of Arctic ice is so extreme that ice thought to have existed for over 1450 years is melting now. (None of the sea ice is really ancient, even the “old” ice recycles over geologically short time periods. But in the near future there will be virtually no “old” ice left in the region.)

According to author Josefino Cosimo, of NASA, “The Arctic region has been warming faster than anywhere else in the globe from 1981 to 2012. Such warming is manifested strongly in all components of the cryosphere in the Northern Hemisphere.”

The following list of chilling, or rather, not chilling, facts is paraphrased from the paper:

Warming in the region has been amplified … with the rate of warming observed to be ~0.60±0.07 o
C per decade in the Arctic (>64 oN) compared to ~0.2 o C per decade globally during the last three decades.

sea ice extent has been declining at the rate of ~3.8% per decade,

while the perennial ice (represented by summer ice minimum) is declining at a much greater rate of ~11.5% per decade.

Spring snow cover [is] declining by –2.12 % per decade for the period 1967 to 2012.

The Greenland ice sheet has been losing mass at the rate of ~123 Gt per year (sea level
equivalence of 0.34 mm per year) during the period from 1993 to 2010

for the period 2005 to 2010, a higher rate of [Greenland ice sheet] mass loss of ~228 Gt per year has been observed.

the average area of mountain glaciers has declined by as much as 10% per decade during the period from 1960 to 2000.

Increases in permafrost temperature have also been measured in many parts of the Northern
Hemisphere while a thickening of the active layer that overlies permafrost and a thinning of
seasonally-frozen ground has also been reported.

Here is the movie version of this review paper:

The review looks at clouds, albedo, and the Arctic Oscillation for insight as to how this is all happening. The Arctic Oscillation is one of those medium-term climate variations (like ENSO) which involves a large scale shift in the movement of air masses from one perennial pattern to another, often accompanied by effects having to do with sea surface temperatures or sea currents.

The Arctic Oscillation (AO), often referred to as Northern Annular Mode (NAM), has been regarded as among the most dominant modes in the [Northern Hemisphere], affecting atmospheric circulation and climate in the Arctic. Its direct impacts on the sea ice cover and wind circulation patterns have been evaluated using AO indices as presented for the entire year on a monthly basis in Figure 9a and for the winter period in Figure 9b. The plots show that the indices for both monthly and for the winter season are mainly positive since 1988 although there are years (e.g., 2010) when they become strongly negative. It has been previously reported that negative AO indices are associated with extensive ice cover while positive indices would correspond to a reduced sea ice cover. However, the indices have become nearly neutral in the recent decade while the sea ice cover continued to decline.

The authors conclude that the link between the Arctic Oscillation and recent changes in the Arctic is unclear. This is hard to interpret without further research but it may be bad news: The recent changes seen in the Arctic and possibly effects not covered in this paper (but discussed frequently on this blog) on global weather don’t seem to be associated with “natural variation.”

The graphic at the top of the post is figure one from the paper, and has this caption: Location Map of the Arctic Region including average sea ice extent (yellow line), sea ice cover during record minimum in summer of 2012 (shades of white), continuous and discontinuous permafrost (shades of pink), glacier locations (gold dots) and snow cover (average location of 50% snow line in black and maximum snow line in green as inferred from MODIS data).

The colorful squiggles up along the top are the first ten years of Arctic Sea ice extent for the period for which we have really good data. So this is 1979 – 1988. There is reason to believe that this is the “normal” sea ice extent track over the year from which we have seen significant deviation over recent decades.

The dark thick line is the average of all of the years from 1979 to 2010. Notice that the first ten years are all above the average except for a few little bits.

The partial line below all of the other lines is the current year, ticking along. I think this graphic provides a good perspective on Arctic Sea ice because we can watch the current state of the ice in comparison to what is reasonably described as “normal.” (I discuss this more here.)

I’ll replace this graphic now and then and re-tweet and re-facebook the post so it all stays in one place. If I’ve not done that in a while and you want me to do it, just let me know.

A few days ago I made a prediction for this year’s minimum Arctic Sea Ice extent. That’s still valid. Or not. Either way, it’s still my prediction.

But looking at the ice over the last few days, we see that for the first time in a while the extent of ice estimated by the NSICD has stopped hugging the -2SD line and is rising upwards like a chilly Phoenix rising out of slush ashes. In fact, one could even say that Arctic Sea Ice has recovered! Just look at the last eight days of data!

Well, even looking at the data at this scale, the sudden upswing in ice is still impressive. This happens frequently, but actually, not every year. Just now and then. Is there an explanation?

Of course there’s an explanation! But I have no idea what it is and the ice experts are not saying much. I’m thinking this is just part of the normal up and down in either measurement error or actual freeziess of ice. Something like this could have more to do with wind than anything else.

This is the time of year, this week, maybe next week, when the maximum Arctic Sea ice extent is typically reached. We are actually past the peak day for some recent years. So keep an eye on this squiggle, it will start to drop soon.

There are several reasons this is interesting. One is the insight it gives in the psychology of climate change denialism. The extent of Arctic Sea ice is important in relation to climate change, so pretending that there has not been a dramatic drop in minimum extent over recent years is essential in order to keep the lie that climate change is not real up and running. Two years ago the drop in sea ice was extremely dramatic, and then last year, the drop in sea ice extent returned to it’s usual merely alarming level, much lower than most recent years, continuing the downward trend. That caused denialists to scream and yell and dance and throw their arms in the air, claiming that the Arctic Sea Ice has recovered. This is roughly equivalent to watching a crash at a NASCAR race with metal flying everywhere, cars on fire, tires rolling away at high speed, but then one of the cars lands on it’s bottom side instead of its top side and everyone goes “Look, there was no accident, yay!”

The main reason this is all important, though, putting the anti-science crowd aside (where they should be put) is simply the fact that as sea ice diminished from year to year, during the summer, the Arctic Sea warms even more, and the planet as a whole gets to warm a bit as well because of the exposure of the dark ocean waters and lack of bright shiny solar-energy-reflecting ice. This has cause the Arctic to warm faster than other regions of the planet. The differential of heat between the warmer equator and cooler poles drives and shapes our climate system. This “amplification” of arctic temperatures relative to the rest of the globe has almost certainly altered weather patterns, and mostly not in a good way.

So, expect more of that, perhaps.

Any bets on which day will be the maximum extent of Arctic Sea ice this year?

I’m going to say that using to the NSICD chart shown here, it will end up being March 19th, tomorrow.

During the northern Winter, much of the Arctic is covered with sea ice. Some of this ice melts during the summer, then it regrows. Over recent years, the amount of ice loss in the summer has tended to increase, almost every year, year after year. In 2012 the loss of sea ice was extreme, falling for much of the melting and re-freezing cycle below any year seen before.

The year 2013 was also extreme, with more ice melting away in the summer than almost every previous year, but not to the extent seen in 2012.

Climate science denialist used this fact to make up a story. In this case, the word “story” is a nice way of saying “lie.” The denialists claimed that Arctic Sea Ice was “recovering.” Well, it was, sort of. Sea ice in 2013 was more extensive than the previous year, but still at a very low level. Part of the “recovery” story was the assertion that the sea ice would not return to “normal” levels year after year. A cycle was simply repeating itself.

The problem with the cycle idea is that there is no really a cycle. In a non-global-warming world there probably would be something that looks like a cycle, or at least a decadal (or something) fluctuation from year to year. But with global warming we have seen a phenomenon called “Arctic Amplification.” This is the warming of the arctic region to a greater extent than most of the rest of the plant. With Arctic Amplification we have seen sea ice extent drop nearly every year for about 20 years. I’ve written about the importance of this here. This does not seem to be a cycle, but rather, a downward trend. The fact that 2012 was extreme makes 2013 look like a reversal, but there is no reason to think that it is.

Now it is Winter in the Arctic. When we look at sea ice extent, we see something interesting. The current level of sea ice is hugging the 98th percentile of observed sea ice extent, at the lower margin. More interestingly, when we compare 2012, the “recovery” year, with the current ice extent, it turns out that the current ice extent is less than the “recovery.”

Jim Pettit, commenting here, noted, “…just wanted to note that denialists have now gone silent on the “recovery” of NH sea ice extent, since that reading is currently several hundred thousands square kilometers lower than it was on this date in 2012, the year of the record melt-out.”

I can not verify Jim’s statement about denialists going silent, but it seems right. I’m not sure what the best way to measure that would be (seems like a lot of work) and I don’t think we have to. Paying too much attention to denialist rhetoric is a waste of time. But I think he may well be right. The answer to the statement “Global warming is not real because SEA ICE RECOVERY” was, several weeks ago, “Right … recovery from an extreme year, but the ice is still less than almost every observed previous year.” The answer to that same assertion is now “Um …. nope.”

The graphic at the top of this post speaks to volume rather than extent. I put it there just to remind everyone that volume is probably even more important, as this reflects loss of long-term ice and also involves a lot more global-warming related energy. If the huge volume of sea ice wasn’t there to melt in the summer, that heat would be elsewhere in the system. When there is virtually no “old ice” left … well, that will be like the ice in your drink melting. It (your drink, the planet, whatever) will get warm and icky.

It is hard to interpret this as meaning anything other than the crisis of Arctic Sea ice melting too much and too fast is over. This is an important thing, because the rapid and widespread melting of sea ice in the Arctic seems to be causing a thing called Arctic Amplification, which means in normal human terms that the Arctic is warmer (amplified) than normal. This causes a decrease in the differential between equatorial heat and polar heat in the Northern Hemisphere which seems to change the way the Jet Streams operate which in turn causes Weather Whiplash, where we have days and days of warm air being drawn north into “ridges” under the Jet Stream or colder air being drawn south into “troughs” in the Jet Stream. Our Minnesota Snowy April, the current midwest Heat Wave, severe cold in Siberia a while back, flooding in Central Europe, etc. etc. all are effects of the warped and slow moving waves in the Jet Stream. Climate math seams to explain the warping and stalling of the Jet Stream as a function of Arctic Amplification, and Arctic Amplification is clearly the result of a warmer northern sea which is caused by exposure of the sea to more energy from the sun because the ice is reduced. The ice is reduced because of global warming, and this is positive feedback effect.

If the Arctic Sea ice melt is “on a decent track” than this might mean a) global warming isn’t really happening and/or b) the Arctic Sea ice to amplification to jet stream warping and stalling to weather whiplash connection isn’t valid. So, that would be important. So let’s see if Andy is Revkin the Right or Revkin the Wrong on this one.

Here is a graph of the track of Arctic Sea ice melt for a period of ten years for the first years in which good measurements are available, from the National Snow & Ice Date Center. Since the recent changes in the Arctic post date this time period, we can take this to be more or less “normal.”

The black, thicker line along the bottom of these other lines is the average ice track from 1981-2010. Note that the sea ice for this ten year baseline period is almost never below that line. The baseline for “on track” is the average of these ten years, and I’ll leave it to you to imagine a line running along the midpoint of the observed ice tracks from 1979 to 1988.

Now, here is the same graph but for the ten year period prior to 2012:

For this later time period, the nature of Arctic Sea ice is fundamentally different than before. This is the period of time that the Arctic Sea has been warming. This is the period of time that Arctic Amplification has becoming more severe. This is the period of time that the weather has been changing. This is the period of time that has been affected by anthropogenic global warming. Sea ice tracks that are within this range are not “on track.” They are probably better characterized as “messed up.”

The following is the same data showing the ice track from 2012 and the present year to date.

The year 2012 was exceptional. It was the most melty of the measured years. This year, is in fact, “on track” but not “on track” to be normal. It is “on track” to be one of the years in which the melting is excessive, and it is “on track” to contribute to Arctic Amplification. It could be worse. It could look like 2012, or even worse, I suppose. But it is not good.

I know it is hard to see all the lines in these graphs when many are selected for display on the Charctic Interactive Sea Ice Graphing Tool, but the years that are not as melty as the present year are all the years prior to the shift documented above, and 2002, 2003, 2004, 2005, and 2006 from after the shift. So, one way of looking at this year is that it is more or less average for the “new normal.” It is “on track” for more weather whiplash.

It is actually good news that the Arctic Sea Ice melting is not worse this year than last year, or even as bad this year as some previous years. But it takes a bit of imagination, or perhaps serves some intent that I find difficult to fathom, to suggest that this year things in the Arctic are on a decent track. Arctic Sea ice melt this year is not decent.

And, all this is about sea ice coverage. There is a more severe problem happening that these graphs don’t show; the melting of old ice, ice that is thicker, with multiple years all jammed up into thicker ice, has been severe over recent years. This ice is important because it forms the foundation on which new sea ice forms every year. Even if the climate went back to “normal” because some technology was invented that sucked all the extra Carbon Dioxide out of the atmosphere to return us to pre-industrial levels was implemented, the lack of old ice would mean that regeneration of sea ice in the Arctic each year would be difficult, and it would probably take several year get the Arctic Sea back to a decent track. For a change.

Here’s Mike Mann’s tweet response to Revkin’s tweet, which says the same thing I say in this blog post but in fewer than 140 characters:

Every northern summer Arctic Sea ice melts away and reforms for winter, but how much melts away seems to be increasing on average, at a rate that surprises climate scientists.

But there are some who see variation from year to year, and there is variation, in a rather unrealistic way. Here is a graph comparing how climate science denialists view arctic sea ice over time, compare to how “climate realists” (i.e., smart people who can read graphs and such) see it:

Now in Kindle, Soon in Print:

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